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CastCheck methodology v0.2 · data through 2026-08-30

San Diego Lindbergh · GraphCast (IFS init) · lead day 7

KSAN · graphcast_ifs · lead 7

Target day = initialization date + 7 days. This page is a permanent link: the numbers change as history accumulates, the address and the methodology version do not.

Scores use the latest model version segment, GRAP_v100, starting 2026-01-01 — days before that ran a different version of the model and are excluded rather than silently pooled. Of the scored days, 1 carry a QC flag on the observation.

JSON for this page CSV of the daily errors Cite this page

Every number for this combination

All four windows × both initializations × both interpolations × both variables. Errors are computed in °C and shown in °F; CI is a 95 % moving-block bootstrap interval. MAE debiased and skill, debiased remove the constant offset of the window first, so a station that the model always reads a degree too warm is not scored as if it had no skill — compare the two skill columns to see how much of the error is a fixed offset. n QC next to n counts days whose observation carries a QC flag.

VariableInitMethod Windown MAE °F MAE debiased Bias °F RMSE °F ±1 °F±2 °F±3 °F Skill Skill, debiased Period
tmax00Zbilinear30d23 1 QC5.70 [3.95, 7.51]2.06-5.70 [-7.51, -3.95]6.30 [4.25, 8.02]0% [0%, 0%]4%13%-0.53+0.402026-08-08 → 2026-08-30
tmax00Zbilinear90d23 1 QC5.70 [3.87, 7.67]2.06-5.70 [-7.67, -3.87]6.30 [4.17, 8.10]0% [0%, 0%]4%13%-0.53+0.402026-08-08 → 2026-08-30
tmax00Zbilinear365d29 1 QC4.99 [3.07, 6.97]2.17-4.99 [-6.97, -3.07]5.75 [3.58, 7.58]7% [0%, 22%]14%24%-0.27+0.402026-01-08 → 2026-08-30
tmax00Zbilinearall29 1 QC4.99 [2.83, 7.12]2.17-4.99 [-7.12, -2.83]5.75 [3.42, 7.75]7% [0%, 25%]14%24%-0.27+0.402026-01-08 → 2026-08-30
tmax00Znearest30d23 1 QC7.46 [5.40, 9.52]2.17-7.46 [-9.52, -5.40]7.97 [5.69, 9.89]0% [0%, 0%]0%4%-0.99+0.372026-08-08 → 2026-08-30
tmax00Znearest90d23 1 QC7.46 [5.37, 9.67]2.17-7.46 [-9.67, -5.37]7.97 [5.60, 10.01]0% [0%, 0%]0%4%-0.99+0.372026-08-08 → 2026-08-30
tmax00Znearest365d29 1 QC6.51 [4.11, 8.83]2.52-6.51 [-8.83, -4.11]7.27 [4.66, 9.38]0% [0%, 0%]10%14%-0.65+0.302026-01-08 → 2026-08-30
tmax00Znearestall29 1 QC6.51 [3.86, 8.98]2.52-6.51 [-8.98, -3.86]7.27 [4.44, 9.46]0% [0%, 0%]10%14%-0.65+0.302026-01-08 → 2026-08-30
tmax12Zbilinear30d23 1 QC5.43 [4.00, 6.86]1.63-5.43 [-6.86, -4.00]5.87 [4.33, 7.20]4% [0%, 12%]4%9%-0.45+0.532026-08-08 → 2026-08-30
tmax12Zbilinear90d23 1 QC5.43 [3.96, 6.93]1.63-5.43 [-6.93, -3.96]5.87 [4.26, 7.25]4% [0%, 13%]4%9%-0.45+0.532026-08-08 → 2026-08-30
tmax12Zbilinear365d28 1 QC4.88 [3.25, 6.48]1.82-4.88 [-6.48, -3.25]5.42 [3.61, 6.92]7% [0%, 17%]7%21%-0.30+0.482026-01-08 → 2026-08-30
tmax12Zbilinearall28 1 QC4.88 [3.00, 6.58]1.82-4.88 [-6.58, -3.00]5.42 [3.30, 7.04]7% [0%, 17%]7%21%-0.30+0.482026-01-08 → 2026-08-30
tmax12Znearest30d23 1 QC7.27 [5.53, 9.02]1.76-7.27 [-9.02, -5.53]7.69 [5.78, 9.29]0% [0%, 0%]4%4%-0.94+0.492026-08-08 → 2026-08-30
tmax12Znearest90d23 1 QC7.27 [5.49, 9.11]1.76-7.27 [-9.11, -5.49]7.69 [5.74, 9.37]0% [0%, 0%]4%4%-0.94+0.492026-08-08 → 2026-08-30
tmax12Znearest365d28 1 QC6.49 [4.33, 8.56]2.23-6.49 [-8.56, -4.33]7.08 [4.73, 9.00]0% [0%, 0%]7%11%-0.73+0.362026-01-08 → 2026-08-30
tmax12Znearestall28 1 QC6.49 [4.06, 8.62]2.23-6.49 [-8.62, -4.06]7.08 [4.46, 8.99]0% [0%, 0%]7%11%-0.73+0.362026-01-08 → 2026-08-30
tmin00Zbilinear30d23 1 QC0.67 [0.45, 0.86]0.65+0.06 [-0.51, 0.57]0.89 [0.63, 1.09]70% [53%, 88%]96%100%+0.59+0.602026-08-08 → 2026-08-30
tmin00Zbilinear90d23 1 QC0.67 [0.39, 0.87]0.65+0.06 [-0.54, 0.58]0.89 [0.53, 1.10]70% [53%, 92%]96%100%+0.59+0.602026-08-08 → 2026-08-30
tmin00Zbilinear365d29 1 QC3.31 [0.55, 8.84]4.38+2.83 [-0.26, 8.54]6.39 [0.76, 11.25]55% [25%, 82%]76%79%+0.23+0.132026-01-08 → 2026-08-30
tmin00Zbilinearall29 1 QC3.31 [0.57, 9.55]4.38+2.83 [-0.26, 9.30]6.39 [0.79, 11.68]55% [20%, 79%]76%79%+0.23+0.132026-01-08 → 2026-08-30
tmin00Znearest30d23 1 QC1.13 [0.71, 1.50]0.73+0.87 [0.24, 1.43]1.26 [0.78, 1.58]48% [15%, 85%]96%100%+0.32+0.552026-08-08 → 2026-08-30
tmin00Znearest90d23 1 QC1.13 [0.67, 1.52]0.73+0.87 [0.16, 1.44]1.26 [0.72, 1.59]48% [12%, 91%]96%100%+0.32+0.552026-08-08 → 2026-08-30
tmin00Znearest365d29 1 QC3.98 [0.93, 9.94]4.60+3.78 [0.51, 9.66]7.07 [1.07, 12.34]38% [3%, 74%]76%79%+0.08+0.082026-01-08 → 2026-08-30
tmin00Znearestall29 1 QC3.98 [0.90, 10.79]4.60+3.78 [0.54, 10.59]7.07 [1.01, 12.84]38% [5%, 75%]76%79%+0.08+0.082026-01-08 → 2026-08-30
tmin12Zbilinear30d23 1 QC0.77 [0.63, 0.99]0.75+0.20 [-0.39, 0.56]1.02 [0.81, 1.34]74% [60%, 88%]96%100%+0.53+0.532026-08-08 → 2026-08-30
tmin12Zbilinear90d23 1 QC0.77 [0.61, 1.00]0.75+0.20 [-0.50, 0.58]1.02 [0.76, 1.36]74% [61%, 91%]96%100%+0.53+0.532026-08-08 → 2026-08-30
tmin12Zbilinear365d28 1 QC2.94 [0.69, 8.11]3.72+2.46 [-0.09, 7.63]5.74 [0.88, 10.47]61% [31%, 82%]79%82%+0.29+0.232026-01-08 → 2026-08-30
tmin12Zbilinearall28 1 QC2.94 [0.68, 8.80]3.72+2.46 [-0.08, 8.48]5.74 [0.87, 10.92]61% [24%, 81%]79%82%+0.29+0.232026-01-08 → 2026-08-30
tmin12Znearest30d23 1 QC1.26 [0.98, 1.50]0.78+1.03 [0.37, 1.45]1.45 [1.18, 1.66]43% [24%, 64%]78%100%+0.24+0.522026-08-08 → 2026-08-30
tmin12Znearest90d23 1 QC1.26 [0.95, 1.53]0.78+1.03 [0.19, 1.46]1.45 [1.14, 1.68]43% [23%, 67%]78%100%+0.24+0.522026-08-08 → 2026-08-30
tmin12Znearest365d28 1 QC3.64 [1.08, 9.25]3.99+3.46 [0.68, 8.96]6.51 [1.29, 11.71]36% [11%, 59%]64%82%+0.12+0.172026-01-08 → 2026-08-30
tmin12Znearestall28 1 QC3.64 [1.08, 10.17]3.99+3.46 [0.69, 9.92]6.51 [1.29, 12.33]36% [10%, 58%]64%82%+0.12+0.172026-01-08 → 2026-08-30

+ model too warm · − model too cold · bias interval includes zero · ★ lowest MAE · = not distinguishable from the leader · ▼ significantly worse · n < 30 greyed and unranked · CI is a 95 % moving-block bootstrap interval.

Daily error, last 90 days

Daily forecast minus observed error in °F for GraphCast (IFS init) at KSAN, lead day 7, 00Z bilinear tmax+20+100-10-202026-08-08: -6.44 °F2026-08-09: -6.62 °F2026-08-10: -5.55 °F2026-08-11: -4.79 °F2026-08-12: -3.86 °F2026-08-13: -1.23 °F2026-08-14: -2.03 °F2026-08-15: -4.58 °F2026-08-16: -3.09 °F2026-08-17: -4.2 °F2026-08-18: -3.91 °F2026-08-19: -4.62 °F2026-08-20: -5.18 °F2026-08-21: -6.61 °F2026-08-22: -6.34 °F2026-08-23: -12.06 °F2026-08-24: -9.08 °F2026-08-25: -8.96 °F2026-08-26: -11.61 °F2026-08-27: -5.02 °F2026-08-28: -5.12 °F2026-08-29: -7.29 °F2026-08-30: -3 °F2026-08-082026-08-30°F, forecast − observed
Forecast − observed, °F, 00Z bilinear daily maximum. The dashed line is zero; the thick line is a centred 7-day mean, drawn only where the whole window is present. Gaps are days with no score, never interpolation. Hover a point for its date and value.
The same series as a table (23 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-3.00
2026-08-29-7.29
2026-08-28-5.12
2026-08-27-5.02
2026-08-26-11.61
2026-08-25-8.96
2026-08-24-9.08
2026-08-23-12.06
2026-08-22-6.34
2026-08-21-6.61
2026-08-20-5.18
2026-08-19-4.62
2026-08-18-3.91
2026-08-17-4.20
2026-08-16-3.09
2026-08-15-4.58
2026-08-14-2.03
2026-08-13-1.23
2026-08-12-3.86
2026-08-11-4.79
2026-08-10-5.55
2026-08-09-6.62
2026-08-08-6.44

Error distribution

Distribution of the signed daily error in °F for GraphCast (IFS init) at KSAN, lead day 7-20 to -18 °F: 0 days-18 to -16 °F: 0 days-16 to -14 °F: 0 days-14 to -12 °F: 1 day-12 to -10 °F: 1 day-10 to -8 °F: 2 days-8 to -6 °F: 5 days-6 to -4 °F: 9 days-4 to -2 °F: 7 days-2 to 0 °F: 4 days0 to 2 °F: 0 days2 to 4 °F: 0 days4 to 6 °F: 0 days6 to 8 °F: 0 days8 to 10 °F: 0 days10 to 12 °F: 0 days12 to 14 °F: 0 days14 to 16 °F: 0 days16 to 18 °F: 0 days18 to 20 °F: 0 daysdashed: P50 |e| 4.79 · P90 |e| 8.98 °F-200+20 °Fn = 29 days
All scored days for 00Z bilinear daily maximum, 20 equal bins. The dashed marks are the 50th and 90th percentiles of the absolute error, mirrored on both sides. Hover a bar for its bin and count.
Bin counts as a table
From °FTo °FDays
-20.00-18.000
-18.00-16.000
-16.00-14.000
-14.00-12.001
-12.00-10.001
-10.00-8.002
-8.00-6.005
-6.00-4.009
-4.00-2.007
-2.00+0.004
+0.00+2.000
+2.00+4.000
+4.00+6.000
+6.00+8.000
+8.00+10.000
+10.00+12.000
+12.00+14.000
+14.00+16.000
+16.00+18.000
+18.00+20.000

Month by month

00Z bilinear daily maximum, newest first.

Monthn MAE °FBias °F
2026-08235.70 -5.70
2026-0162.24 -2.24

Availability

ModelScored period DaysCoverage
GraphCast (IFS init)2026-01-08 → 2026-08-30 29
GraphCast (IFS init)2026-01-08 → 2026-08-30 29
GraphCast (IFS init)2026-01-08 → 2026-08-30 28
GraphCast (IFS init)2026-01-08 → 2026-08-30 28

Compared with other models

Paired bootstrap on the days both models cover (90d, 00Z, bilinear, daily maximum). Negative means GraphCast (IFS init) has the lower MAE. "Distinguishable" means the 95 % interval excludes zero.

Other modelCommon days MAE difference °FDistinguishable
ECMWF AIFS Single 23 +2.36 [1.18, 3.54] yes
NCEP GFS 23 +1.98 [0.89, 2.97] yes
ECMWF IFS HRES 18 +0.59 [-0.73, 2.39] no
Persistence (baseline) 23 +1.97 [0.62, 3.24] yes

Cite this page

ShortCastCheck, KSAN graphcast_ifs lead 7, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KSAN/model/graphcast_ifs/lead/7/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KSAN (San Diego Lindbergh), model graphcast_ifs, lead day 7. Methodology version 0.2, schema version 0.1, data through 2026-08-30. Accessed 2026-08-31. https://castcheck.zifanzhang.com/station/KSAN/model/graphcast_ifs/lead/7/

Accessed2026-08-31 (data through 2026-08-30; page built 2026-08-31T03:52:06+00:00)

JSON CSV all scores methodology v0.2 licence